/Engine/Source/Editor/UnrealEd/Public/EdGraphUtilities.h
Also optionally populates *OutClonedNodes with the list of cloned objects.
static void CloneAndMergeGraphIn ( [UEdGraph](API\Runtime\Engine\EdGraph\UEdGraph) * MergeTarget, [UEdGraph](API\Runtime\Engine\EdGraph\UEdGraph) * SourceGraph, [FCompilerResultsLog](API\Editor\UnrealEd\Kismet2\FCompilerResultsLog) & MessageLog, bool bRequireSchemaMatch, bool bInIsCompiling, [TArray](API\Runtime\Core\Containers\TArray)< [UEdGraphNode](API\Runtime\Engine\EdGraph\UEdGraphNode) * > * OutClonedNodes )